Chair

ABSTRACT

A chair is provided with a seat, a chair back control unit, a chair back, and two armrest units. The chair back is pivotally coupled to the seat by sleeving the engaging portions of the seat onto the clamp members of the chair back. The assembling of the chair back onto the seat can be easily done by the actions of inserting and clamping, so that the assembly operation is quick and easy without using any screws, and therefore the assembly cost is reduced. Furthermore, the angle and height of the armrest units can be easily adjusted, and the chair back is foldable. With the abovementioned structural arrangements, the number of the parts of the chair is substantially reduced.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a chair, and more particularly to a chair with a foldable chair back, and the angle and height of the armrest units are adjustable.

2. Description of the Prior Art

Adjustable chairs are mostly adjustable in chair back and armrests. However, the adjustment structures of the back and armrests of the existing chairs are complicated, and the adjustable chairs must use rotary shaft to achieve rotating function, and use screws and bolts to fix the parts of the chair together. Therefore, in addition to the disadvantages of complicated structure and high cost, the complexity and difficulty of assembly also increase as the increase of adjustment functions.

The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide an adjustable chair which has a simple structure and is easy to assemble.

To achieve the above objective, a chair in accordance with the present invention comprises a seat and a chair back,

The seat is provided at two opposed sides thereof with an engaging portion which is a hollow cylindrical structure, each of the engaging portions being provided with two slots.

The chair back is provided with two opposed arm portions, each of the arm portions includes a clamp member which is cylindrical structure formed with an annular groove around an outer peripheral surface thereof. The clamp members of the arm portions are inserted in the engaging portions of the seat and fixed therein by two elastic fixing members in such a manner that the annular grooves of the clamp members are aligned to the slots of the engaging portions. The elastic fixing members are each provided with a clamp notch for clamping the engaging portions and two clamp sections which are inserted through the slots and into the annular grooves of the clamp members.

The assembling of the chair back onto the seat can be easily done by the actions of inserting and clamping, so that the assembly operation is quick and easy.

The chair of the present invention can be easily assembled without using any screws, and the assembly cost is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an assembly view of a. chair in accordance with the present invention;

FIG. 2 is an exploded view of the chair in accordance with the present invention;

FIG. 3 is a perspective view of the seat of the chair in accordance with the present invention, wherein the rotary member restricts the chair back from pivoting;

FIG. 4A is a cross sectional view of the seat of the chair in accordance with the present invention, wherein the rotary member restricts the chair back from pivoting;

FIG. 4B is an enlarged view of a part of FIG. 4A;

FIG. 5A is a perspective view of the chair in accordance with the present invention, wherein the chair back is rotatable;

FIG. 5B is an enlarged view of a part of FIG. 5A;

FIG. 6 is a perspective cross sectional view showing a part of the connecting structures between the chair back and the seat of the chair in accordance with the present invention;

FIG. 7 is a cross sectional view showing a part of the connecting structures between the chair back and the seat of the chair in accordance with the present invention;

FIG. 8 is a cross sectional view showing a part of the connecting structures between the chair back and the seat of the chair in accordance with the present invention, wherein the armrest unit is in a non-rotatable state;

FIG. 9 is a cross sectional view showing a part of the connecting structures between the chair back and the seat of the chair in accordance with the present invention, wherein the armrest unit is a rotatable state;

FIG. 10 is an illustrative view showing that the armrests of the chair of the present invention are being pivoted; and

FIG. 11 is an illustrative view showing a. part of the connecting structures between the chair back and the armrest units of the chair in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be clearer from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention.

Referring to FIGS. 1-11, a chair in accordance with a preferred embodiment of the present invention comprises: a seat 10, a chair back control unit 20, a chair back 30, and two armrest units 40.

The seat 10 is provided with a seat frame 11 connected to a base 12. The seat frame 11 includes a top surface 111 and a bottom surface 112 which is connected to the base 12. The seat frame 11 is provided for mounting a seat cushion A. Each of two opposed sides of the seat frame 11 is provided with an engaging portion 13 which is a hollow cylindrical structure. Each of the engaging portions 13 is provided with two slots 131. On the top surface 111 of the seat frame 11 is provided a control platform 14 which is formed with a through hole 141 and two opposed semicircular positioning protrusions 142. The seat frame 11 is further formed with an opening 113 which is located adjacent to the control platform 14, and there is a horizontal distance DI between the opening 113 and the through hole 141.

The chair back control unit 20 includes a rotary member 21 and a control button 22. The rotary member 21 is rotatably disposed on the seat frame 11 and includes an assembling portion 211 and two opposed arc-shaped positioning cavities 212 around a periphery of the assembling portion 211. The periphery of the rotary member 21 includes an arc-shaped engaging edge 213 and a disengaging edge 214. A direction extending from the disengaging edge 214 through the assembling portion to the arc-shaped engaging edge 213 is defined as a longitudinal axis X which is perpendicular to the disengaging edge 214 and consists of a first axis section Xi and a second axis section X2. The first axis section X1 is a distance between the disengaging edge 214 and the assembling portion 211, and the second axis section X2 is a distance between the assembling portion 211 and the arc-shaped engaging edge 213. The length of the first axis section X1 is equal to the length of the horizontal distance D1 and less than the length of the second axis section X2. The rotary member 21 is mounted on the control platform 14 in such a manner that the assembling portion 211 is aligned to the through hole 141 of the control platform 14, the two arc-shaped positioning cavities 212 are aligned to the two positioning protrusions 142, and the disengaging edge 214 or the arc-shaped engaging edge 213 of the rotary member 21 inserts into the opening 113.

The control button 22 is provided with an assembling section 221 on one surface and a control section 222 on another surface thereof The assembling section 221 is inserted from the bottom surface 112 of the seat frame 11 into the through hole 141 of the seat frame 11 and fixed to the assembling portion 211 of the rotary member 21, so that the control section 222 of the control button 22 can be rotated by a user. Rotating the control button 22 can drive the rotary member 21 to rotate, so as to change the position of the rotary member 21 with respect to the opening 113, and the rotary member 21 rotates around the assembling portion 211 which serves as a rotation center of the rotary member 21.

The chair back 30 includes a back frame 31 with two opposed arm portions 32. The back frame 31 is provided for mounting a back cushion B and has a stop piece 311. When the arc-shaped engaging edge 213 of the rotary member 21 of the chair back control unit 20 inserts into the opening 113, it will be stopped against the stop piece 311 to stop the chair back 30 from rotating. When the disengaging edge 214 of the rotary member 21 inserts in the opening 113, the rotary member 21 won't be in contact with the stop piece 311, so as to allow the chair back 30 to rotate.

Each of the arm portions 32 includes a clamp member 33 which is cylindrical structure formed with an annular groove 331 around an outer peripheral surface thereof, the two clamp members 33 are located opposite to each other. The two arm portions 32 are hollow structures and each provided with a receiving chamber 321 and an inserting hole 322 running through the receiving chamber 321. On an inner surface of the receiving chamber 321 of each of the arm portions 32 is formed a guiding block 34 which is provided with a plurality of slanting grooves 341. The clamp members 33 of the arm portions 32 are inserted in the engaging portions 13 of the seat 10 and fixed therein by two elastic fixing members 35 in such a manner that the annular grooves 331 of the clamp members 33 are aligned to the slots 131 of the engaging portions 13. The elastic fixing members 35 are U-shaped and each provided with a clamp notch 351 for clamping the engaging portions 13 and two clamp sections 352 which are inserted through the slots 131 and into the annular grooves 331 of the clamp members 33.

The two armrest units 40 each include a bottom cover 41, an elastic engaging member 42, a pin 43, a stop member 44, a spring 45, a control member 46 and a top cover 47.

Each of the bottom cover 41 includes a seat portion 411, a penetrating hole 412 which is formed on the seat portion 411 and penetrates the bottom cover 41, two positioning protrusions 413, and a lateral hole 414. The penetrating hole 412 is aligned with a corresponding one of the inserting holes 322.

The elastic engaging member 42 is fixed to the pin 43, and the stop member 44 is fixed to the bottom cover 41. The pin 43 is provided with an inner hole 432 and an annular positioning groove 431 which is located at one end of the pin 43. The inner hole 432 is formed with two stop rotation grooves 433. The stop member 44 is C-shaped and positioned in the annular positioning groove 431. On an outer surface of the pin 43 is formed a swing slot 434 which includes two slanting surfaces 435. The pin 43 further includes an inserting groove 436 in communication with the swing groove 434. The elastic engaging member 42 includes a middle section 421, and a first engaging section 422 and a second engaging section 423 at two ends of the middle section 421, respectively. The elastic engaging member 42 is fixed on the pin 43 in such a manner that the middle section 421 is received in the swing groove 434, and the second engaging section 423 is received in the inserting groove 436. Then the pin 43 is inserted from the penetrating hole 412 of the bottom cover 41 through the inserting hole 322 of the arm portion 32 and finally into the receiving chamber 321 of a corresponding one of the arrn portions 32, in such a manner that the first engaging section 422 of the elastic engaging member 42 is received in the slanting grooves 341 of the guiding block 34, and the stop member 44 stops against the seat portion 411 to prevent the pin 43 from sinking into the seat portion 411.

The control member 46 includes two elongated holes 461 and a control protrusion 462 at one side thereof and a stop rotation block 463 at another side thereof The stop rotation block 463 is configured to fit the shape of the stop rotation grooves 433. The control protrusion 462 is provided at a surface thereof with a receiving groove 464 which is located toward the stop rotation block 461 The control protrusion 462 of the control member 46 is inserted in the bottom cover 41 and exposed out the bottom cover 41 the spring 45 has one end received in the receiving groove 464 and another end abutted against the seat portion 411 of the bottom cover 41. The positioning protrusions 413 of the bottom cover 41 are inserted in the elongated holes 461 of the control member 46, and the stop rotation block 463 is inserted through the inner hole 432 and into the stop rotation grooves 433 of the pin 43.

The top cover 47 is mounted on the bottom cover 41.

What mentioned above are the structural relations of the respective parts of the chair of the present invention. With the abovementioned structural arrangements, the number of the parts and assembly difficulty of the chair of the present invention can be substantially reduced. The assembly operation of the chair is explained as follows:

Firstly, the chair back 30 is pivotally coupled to the seat 10 by sleeving the engaging portions 13 of the seat 10 onto the clamp members 33 of the arm portions 32 of the chair back 30, as shown in FIGS. 6 and 7. After the chair back 30 is pivoted to the seat 10, the elastic fixing members 35 are clamped onto the engaging portions 13 to prevent the disengagement of the clamp members 33. The assembling of the chair back 30 onto the seat 10 can be easily done by the actions of inserting and clamping, so that the assembly operation is quick and easy.

Then, since the seat 10 is provided with the chair back control unit 20, the chair back control unit 20 can use the control button 22 to rotate the rotary member 21. As shown in FIGS. 3 and 4, when it extends out of the opening 113, the arc-shaped engaging edge 213 of the rotary member 21 is stopped against the stop piece 311 of the chair back 30 to stop the chair back 30 from rotating, so as to maintain the chair back 30 in an upright position. Tb fold the chair hack 30, the user can rotate the rotary member 21 by rotating the control button 22 of the chair back control unit 20 to make the disengaging edge 214 of the rotary member 21 aligned with the opening 113. At this moment, since the first axis section X1 is shorter than the horizontal distance D1 the disengaging edge 214 won't extend out of the opening 113, as shown in FIG. 5, namely, the rotary member 21 doesn't contact the stop piece 311 of the chair back 30, so that the chair back 30 is rotatable and therefore can be folded to volume. Rotating the rotary member 21 can lock the chair back 30 or make the chair back 30 foldable with respect to the seat 10, hence the chair of the present invention has a simple structure and easy to use.

The height each of the armrest unit 40 can also be adjusted by pulling the bottom cover 41 to make the pin 43 move the elastic engaging member 42 which is located in the swing slot 434 of the pin 43. When the elastic engaging member 42 moves, the first engaging section 422 will slide along the slanting grooves 341 of the guiding block 34. By such, arrangements, when the user pulls the bottom cover 41, the pin 43 will be moved upward in a stepped manner under the guide of the elastic engaging member 42 and the guiding block 34, so that the user can feel that the height of the armrest unit 40 is adjusted in a stepped manner when the elastic engaging member 42 is engaged in different slanting grooves 341.

The angle of each of the armrest unit 40 is also adjustable, as shown in FIGS. 8-10, the user pushes the control member 46 to move and to press the spring 45, accordingly the stop rotation block 463 of the control member 46 is disengaged from the stop rotation grooves 433 to make the pin 43 disengage from the control member 46 to make the armrest unit 40 rotatable, namely, the angle of the armrest unit 40 is adjustable. When the angle of the armrest unit 40 is adjusted, the pin 43 of the armrest unit 40 will rotate, meanwhile, the slanting surfaces 435 will push the elastic engaging member 42 to disengage from the slanting grooves 341, so that the height of the armrest unit 40 can be adjusted more smoothly.

The stop member 44 of the armrest unit 40 is positioned in the annular positioning groove 431 to prevent the pin 43 from sinking into the seat portion 411. Meanwhile, the two ends of the elastic engaging member 42 are engaged in the slanting grooves 341 of the guiding block 34 and the inserting groove 436 of the pin 43 to restrict the pin 43 in the arm portion 32 of the chair back 30. Hence, the chair of the present invention can be easily assembled without using any screws, and the assembly cost is reduced.

While we have shown and described various embodiments in accordance with the present invention, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention. 

What is claimed is:
 1. A chair comprising: a seat provided at two opposed sides thereof with an engaging portion which is a hollow cylindrical structure, each of the engaging portions being provided with two slots; and a chair back with two opposed arm portions, each of the arm portions including a clamp member which is cylindrical structure formed with an annular groove around an outer peripheral surface thereof; the clamp members of the arm portions being inserted in the engaging portions of the seat and fixed therein by two elastic fixing members in such a manner that the annular grooves of the clamp members are aligned to the slots of the engaging portions, each of the elastic fixing members being provided with a clamp notch for clamping the engaging portions and two clamp sections which are inserted through the slots and into the annular grooves of the clamp members.
 2. The chair as claimed in claim 1, wherein the elastic fixing members are U-shaped.
 3. The chair as claimed in claim 1, wherein the seat is provided with a seat frame connected to a base, the seat frame is provided for mounting a seat cushion, the chair back includes a back frame with the two opposed arm portions, and the back frame is provided for mounting a back cushion.
 4. The chair as claimed in claim 3, wherein the seat frame is formed with an opening, the back frame is provided with a stop piece, the seat includes a chair back control unit which includes a rotary member rotatably disposed on the seat frame, a periphery of the rotary member includes an arc-shaped engaging edge and a disengaging edge which are alternatively inserted into the opening of the seat frame, when the arc-shaped engaging edge of the rotary member of the chair back control unit inserts into the opening, it will be stopped against the stop piece to stop the chair back from rotating, and when the disengaging edge of the rotary n ember inserts in the opening, the rotary member won't be in contact with the stop piece, so as to allow the chair hack to rotate.
 5. The chair as claimed in claim 4 wherein the seat frame is provided with a through hole, the rotary member includes an assembling portion d is mounted on the control platform in such a manner that the assembling portion is aligned to the through hole of the platform, the chair back control unit includes a control button which is provided with an assembling section on one surface and a control section on another surface thereof, the assembling section is inserted into the through hole of the frame and fixed to the assembling portion of the rotary member, so that the control section of the control button is allowed to be rotated by a user, rotating the control button can drive the rotary member to rotate, so as to change a position of the rotary member with respect to the opening.
 6. The chair as claimed in claim 5, wherein there is a horizontal distance between the opening and the through hole, a periphery of the rotary member includes an arc-shaped engaging edge and a disengaging edge a direction extending from the disengaging edge through the assembling portion to the arc-shaped engaging edge is defined as a longitudinal axis which is perpendicular to the disengaging edge and consists of a first axis section and a second axis section, the first axis section is a distance between the disengaging edge and the assembling portion, and the second axis section is a distance between the assembling portion and the arc-shaped engaging edge, a length of the first axis section is equal to a length of the horizontal distance and less than a length of the second axis section.
 7. The chair as claimed in claim 5, wherein the seat is provided with a seat frame connected to a base, the seat frame includes a top surface and a bottom surface which is connected to the base, on the top surface of the seat frame is provided a control platform which is formed with the through hole and two opposed semicircular positioning protrusions, the opening is located adjacent to the control platform, the rotary member is provided with two opposed arc-shaped positioning cavities around a periphery thereof, and the two arc-shaped positioning cavities are aligned to the two positioning protrusions.
 8. The chair as claimed in claim 1, wherein an armrest unit is disposed at each of the arm portions, the arm portions are hollow structures and each provided with a receiving chamber and an inserting hole running through the receiving chamber, each of the armrest units includes a bottom cover, an elastic engaging member, a pin, a stop member, a spring, a control member and a top cover; the bottom cover includes a seat portion, a penetrating hole which is formed on the seat portion and penetrates the bottom cover, t ^(.)o positioning protrusions, and a lateral hole, the penetrating hole is aligned with a corresponding one of the inserting holes; the pin is provided with an inner hole and an annular positioning groove which is located at one end of the pm, the inner hole is formed with t ^(,)o stop rotation grooves, the stop member is C-shaped and positioned in the annular positioning groove, the pin is inserted from the penetrating hole of the bottom cover through the inserting hole of the arm portion and finally into the receiving chamber, and the stop member stops against the seat portion to prevent the pin from sinking into the seat portion; the control member includes two elongated holes and a control protrusion at one side thereof and a stop rotation block at another side thereof, the stop rotation block is configured to fit the shape of the stop rotation grooves, the control protrusion is provided at a surface thereof with a receiving groove which is located toward the stop rotation block, the control protrusion of the control member is inserted in the bottom cover and exposed out the bottom cover, the spring has one end received in the receiving groove and another end abutted against the seat portion of the bottom cover, the positioning protrusions of the bottom cover are inserted in the elongated holes of the control member, and the stop rotation block is inserted through the inner hole and into the stop rotation grooves of the pin; and the top cover is mounted on the bottom cover.
 9. The chair as claimed in claim 8, wherein each of the armrest units includes an elastic engaging member, on an inner surface of the receiving chamber of each of the arm portions is formed a guiding block which is provided with a plurality of slanting grooves, on an outer surface of the pin is formed a swing slot which includes two slanting surfaces, the pin further includes an inserting groove in communication with the swing groove, the elastic engaging member includes a middle section, and a first engaging section and a second engaging section at two ends of the middle section, respectively, the elastic engaging member is fixed on the pin in such a manner that the middle section is received in the swing groove, and the second engaging section is received in the inserting groove. 